csj-161127083146power point presentation

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1. Presented By
Niloy Saha
Control Statements in Java
Departmentof Computer Science &Engineering

2. Control Statements
Selection
Iteration
Jump
Outlines
2

3. Selection
Selection Statements
Switch Statement
Selection Statements are also called Decision Making Statements.
Selection Statements
3

4. if Statements
Simple if
if else
if-else-if Ladder
Nested if
if Statements
4

5. Simple if
Syntax:
if(condition)
{
statement1;
}
Purpose:Thestatementswillbeevaluatedifthevalueoftheconditionistrue.
5

6. Simple if
Start
End
Condition
Statements
False
True
Flow Chart:
6

7. Example
7

8. if else
Syntax:
if(condition)
{
statement1;
}
else
{
statement2;
}
Purpose:Thestatement1isevaluatedifthevalueoftheconditionistrueotherwise
statement2istrue.
8

9. if else
False
True
Flow Chart:
Start
End
Condition
Statement 1 Statement 2
9

10. Example
10

11. If-else-if Ladder
Syntax :
if(condition)
statements;
else if(condition)
statements;
else if(condition)
statements;
...
...
else
statements;
11

12. Examples
import java.util.Scanner;
class Day
{
public static void main(String args[])
{
Scanner s = new Scanner(System.in);
System.out.println("Enetday between 0 to 6 Day = ");
intday = s.nextInt();
if (day == 0)
{
System.out.println("\n Sunday");
}
else if (day == 1)
{
System.out.println("\n Monday");
}
else if (day == 2)
{
System.out.println("\n Tuesday");
}
else if (day == 3)
{
System.out.println("\n Wednesday");
}
else if (day == 4)
{
System.out.println("\n Thursday");
}
else if (day == 5)
{
System.out.println("\n Friday");
}
else
{
System.out.println("\n Saturday");
}
}
}
12

13. Nested if
•A nested if is an if statement that is the target of another if or else.
•Nested ifs are verycommon in programming.
Syntax :
if(condition)
{
if(condition)
statements....
else
statements....
}
else
{
if(condition)
statements....
else
statements....
}
13

14. Example
14

15. switch
Syntax :
switch (expression)
{
case value 1 :
statement 1 ; break;
case value 2 :
statement 2 ; break;
...
...
case value N :
statement N ; break;
default :
statements ; break;
}
Purpose: The statements N will be evaluated if the value of the logical expression is true.
15

16. switch
Flow Chart:
Case A
Case B
…
default
False
False
False
Case A Statements
break;
Case B Statements
break;
Case C Statements
break;
Default Statements
Start
Variable or Expression
True
True
True
End
16

17. Example
17

18. Iteration Statements
Iterations/ Loops
while
do while
for
Each loop has four types of
statements :
Initialization
Condition checking
Execution
Increment / Decrement
18

19. while
Syntax:
initialization
while(final value)
{
statements;
increment/decrement;
}
Purpose: To evaluate the statements from initial value to final value with given
increment/decrement.
m=1
while(m<=20)
{
System.out.println(m);
m=m+1;
}
19

20. Example
class while1
{
public static void main(String args[])
{
inti=1;
while(i<=10)
{
System.out.println("\n" + i);
i++;
}
}
}
Output :
1
2
3
4
5
6
7
8
9
10
print values from 1 to 10
20

21. do while
Syntax:
initialization
do
{
statements;
increment/decrement;
}
while(finalvalue);
Purpose:Toevaluatethestatementsfrominitialvaluetofinalvaluewithgiven
increment/decrement.
m=1
do
{
System.out.println(m);
m=m+1;
}
while(m==20);
21

22. Example
class dowhile1
{
public static void main(String args[])
{
inti= 1;
intsum = 0;
do
{
sum = sum + i;
i++;
}while (i<=10);
System.out.println("\n\n\tThesum of 1 to 10 is .. " + sum);
}
}
Output :
The sum of 1 to 10 is .. 55 22

23. for
Syntax:
for(initialization;finalvalue;increment/decrement)
{
statements;
}
Purpose:Toevaluatethestatementsfrominitialvaluetofinalvaluewithgiven
increment/decrement.
for(m=1;m<=20;m=m+1)
{
System.out.println(m);
}
23

24. Example
class for1
{
public static void main(String args[])
{
inti;
for (i=0;i<5;i++)
{
System.out.println("\nExampleof for loop ");
}
}
Output :
Example of for loop
Example of for loop
Example of for loop
Example of for loop
Example of for loop
24

25. Jump Statements
Jump
break
continue
return
25

26. The break statement
Thisstatementisusedtojumpoutofaloop.
Breakstatementwaspreviouslyusedinswitch–casestatements.
Onencounteringabreakstatementwithinaloop,theexecutioncontinueswiththenext
statementoutsidetheloop.
Theremainingstatementswhichareafterthebreakandwithintheloopareskipped.
Breakstatementcanalsobeusedwiththelabelofastatement.
Astatementcanbelabeledasfollows.
statementName:SomeJavaStatement
Whenweusebreakstatementalongwithlabelas,
breakstatementName;
26

27. Example
class break1
{
public static void main(String args[])
{
inti= 1;
while (i<=10)
{
System.out.println("\n" + i);
i++;
if (i==5)
{
break;
}
}
}
}
Output :
1
2
3
4
27

28. continue Statement
Thisstatementisusedonlywithinloopingstatements.
Whenthecontinuestatementisencountered,thenextiterationstarts.
Theremainingstatementsintheloopareskipped.Theexecutionstartsfromthe
topofloopagain.
28

29. Example
class continue1
{
public static void main(String args[])
{
for (inti=1; i<1=0; i++)
{
if (i%2 == 0)
continue;
System.out.println("\n" + i);
}
}
}
Output :
1
3
5
7
9
29

30. The return Statement
Thelastcontrolstatementisreturn.Thereturnstatementisusedto
explicitlyreturnfromamethod.
Thatis,itcausesprogramcontroltotransferbacktothecallerofthe
method.
Thereturnstatementimmediatelyterminatesthemethodinwhichitis
executed.
30

31. Example
class Return1
{
public static void main(String args[])
{
booleant = true;
System.out.println("Before the return.");
if(t)
return; // return to caller
System.out.println("This won't execute.");
}
}
Output :
Before the return.
31

32. Thank You